| Value | Category | Cases | |
|---|---|---|---|
| 1 | At once | 7 |
25%
|
| 2 | Within a month | 2 |
7.1%
|
| 3 | Later than a month | 4 |
14.3%
|
| 4 | Don't know | 15 |
53.6%
|
| Sysmiss | 4516 |